Alignment stage apparatus

ABSTRACT

An alignment stage apparatus including a base structure and a movable stage, which can move along a surface of the base structure so as not to be in contact with the base structure. The apparatus includes a plurality of power transmission coils buried under the surface of the base structure, a power reception coil attached to the movable stage to oppose the surface, a switch unit configured to sequentially switch, of the plurality of power transmission coils, those that are to be energized to feed power in accordance with a position of the movable stage, and a power feed unit configured to supply AC power to the power transmission coils to be energized through the switch unit. The power reception coil includes a plurality of power reception coils arrayed in a driving direction of the movable stage, and the power reception coils and power transmission coils are phase-shifted from each other by 180°/n where n is the number of power reception coils arrayed in the driving direction of the movable stage.

FIELD OF THE INVENTION

The present invention relates to an alignment stage apparatus used in adevice manufacturing apparatus, or the like, which manufactures a devicehaving a fine pattern, e.g., a semiconductor device.

BACKGROUND OF THE INVENTION

Japanese Patent Laid-Open No. 10-270535 shows the structure of analignment stage apparatus in a semiconductor exposure apparatus. FIG. 7is a plan view of the alignment stage apparatus described in JapanesePatent Laid-Open No. 10-270535, and FIG. 8 is a side view of the same.

In the conventional alignment stage apparatus as shown in FIG. 7, coils102 are arranged like a matrix in a base structure 101, and permanentmagnets 112 are similarly arranged like a matrix under a movable stagemain body 103. When a current is supplied to the driving coils 102opposing the permanent magnets 112, the movable stage main body 103receives a thrust by the Lorentz force and is driven.

An electrostatic chuck 106, which holds a wafer by the electrostaticforce, and various types of sensors 104, e.g., a sensor for monitoringthe light quantity of a light source and an alignment sensor, arearranged on the movable stage main body 103.

Bearings 107 for supporting the weight of the stage are arranged on thelower surface of the movable stage main body 103. The movable stage mainbody 103 is guided while sliding on the surface of the base structure101 whose flatness is compensated for. Alternatively, the weight of themovable stage main body 103 can be supported by the Lorentz force. Inthis case, magnets are arranged on the lower surfaces of the bearings aswell.

Two bar mirrors 105 are arranged on the movable stage main body 103 tobe perpendicular to each other. A laser interferometer 108 mounted on aninterferometer support 113 measures the position of the movable stagemain body 103. A current is supplied to the driving coils 102 to alignthe movable stage main body 103 such that the measured position of themovable stage main body 103 coincides with a target value from a controldevice.

In the conventional stage structure shown in FIGS. 7 and 8, powerfeeding means 110 and power receiving means 109 are provided forsupplying power to the electrostatic chuck 106, sensor 104, and thelike, on the movable stage main body 103. The received power is storedin a rechargeable battery 111. As the power feeding means, for example,a method of mechanically bringing an electrical contact into contact,and a method of opposing electromagnetic cores 114 to each other to forma magnetic circuit and supplying power in a non-contact manner byelectromagnetic induction, as shown in Japanese Patent Laid-Open No.8-51137, are available.

FIG. 9 shows the schematic structure of the method of supplying power byelectromagnetic induction. When an AC power supply 127 of several kHz toseveral tens of kHz is connected to the transmission sideelectromagnetic core, power is supplied to the reception sideelectromagnetic core by electromagnetic induction. The supplied powercharges the battery 111.

In the conventional structure described above, when a movable stagereturns to a wafer transfer position to transfer a wafer, the powerfeeding means and power receiving means oppose each other to charge thebattery. In an exposure operation, or the like, during which the movablestage separates from the wafer transfer position, the power for theelectrostatic chuck and sensors is supplied from the battery 111. Afterthe exposure is complete, when the movable stage returns to the wafertransfer position again, the battery 111 is charged again.

According to Japanese Patent Laid-Open No. 8-51137, in a transportapparatus, which electrically chucks and transports a silicon wafer, ameans for supplying power by electromagnetic induction is provided ateach stop position along the transport path, so that the electrostaticchucking means is charged (for chucking) or discharged (for release).Although a capacitor for keeping the voltage is mounted, since powerconsumption for electrostatic chucking is very small, no battery ismounted.

In the conventional example described in Japanese Patent Laid-Open No.10-270535, the power feeding means and power receiving means areprovided for supplying power to the electrostatic chuck and sensors onthe movable stage main body, as shown in FIG. 7. The received power isstored in the rechargeable battery. Therefore, power can be suppliedonly when the stage is located at a certain predetermined position, suchas a wafer transfer position.

With this structure, since the power can only be supplied at a specificposition, such as the wafer transfer position, the stage main body mustbe returned, when necessary, to a position where power can be supplied,to charge the battery. This prolongs the process interval of exposure,or the like, or interrupts the process, to accordingly decrease thethroughout. The battery is charged after it is discharged to a certaindegree, and it takes time to charge the battery. The alignment apparatuscannot start the next operation until charging is complete. This isdisadvantageous in terms of throughput.

Also, in the conventional example described in Japanese Patent Laid-OpenNo. 8-81137, power can only be supplied at a specific position, such asa stop position, and, accordingly, cannot be supplied at an arbitraryposition or timing. If a battery must be mounted on the movable stagefrom the viewpoint of power consumption in the movable stage, the sameproblems as those of the conventional example described in JapanesePatent Laid-Open No. 10-270535 arise.

Alternatively, no battery will be used and power may be supplied throughan electrical cable. In this case, however, the accuracy of the movablestage is degraded by the disturbance of the cable. With a stageapparatus having a flat structure, it is difficult to arrange andpackage the cable. If the cable is rubbed, dust may be produced toattach to the wafer. If the jacket of the cable degrades, trouble, suchas insufficient insulation or wire disconnection, may occur.

SUMMARY OF THE INVENTION

The present invention has been made in view of the unsolved problems ofthe prior art described above, and has as its object to provide analignment stage apparatus in which power can be supplied in anon-contact manner at an arbitrary position or timing without using anyelectrical cable, particularly, an alignment stage apparatus suitable asa stage apparatus having a flat structure.

In order to achieve the above object, an alignment stage apparatusaccording to the present invention, including a base structure and amovable stage, which can move along a surface of the structure so as notto be in contact with the base structure, comprises a plurality of powertransmission coils buried under the surface of the base structure, apower reception coil attached to the movable stage to oppose thesurface, switching means for sequentially switching, of the plurality ofpower transmission coils, those that are to be energized to feed powerin accordance with a position of the movable stage, and power feedingmeans for supplying AC power to the power transmission coils to beenergized through the switching means.

In a preferred embodiment of the present invention, at least some of theplurality of power transmission coils are also used as driving coils,which move the movable stage. The power reception coil comprises aplurality of power reception coils arrayed in a driving direction of themovable stage. In this case, the power reception coils are preferablyarranged to be phase-shifted from the power transmission coils. Toarrange the power reception coils to be phase-shifted is to set the gapamong the power reception coils to be different from the pitch of thepower transmission coils and an integer multiple of the pitch.

More specifically, the power reception coils and power transmissioncoils are phase-shifted from each other by 180°/n where n is the numberof power reception coils arrayed in the driving direction of the movablestage. Namely, the gap among the power reception coils is set to (K±½n)(where K is an integer of 1 or more and can change between adjacentpairs of power reception coils) times the pitch of the powertransmission coils. In this case, when one power reception coil opposesone power transmission coil, the remaining power reception coils opposeno power transmission coils. When outputs from the plurality of powerreception coils are to be rectified, an output obtained when connectingthe power transmission coils in series may be input to a rectifyingcircuit. Alternatively, outputs from the respective power receptioncoils may be input to the rectifying circuit and rectified separately,and synthesized.

If the frequency of the AC power is set at a resonance frequencydetermined by load and mutual inductance between the power transmissioncoils and power reception coils, power transmission can be performedmore efficiently.

Power is transmitted and received by superposing a control signal on theAC power, so that an electrical circuit on the movable stage and acontrol device provided to the base structure can communicate with eachother.

A rechargeable secondary battery may be mounted on the movable stagetogether with or in place of a smoothing capacitor for a DC circuit.

The present invention can be applied when the driving direction of themovable stage comprises either a one- or two-dimensional direction alongthe surface of the base structure.

According to the present invention, the plurality of power transmissioncoils to be electromagnetically coupled to the power reception coilsattached to the movable stage are buried in the base structure. Thepower transmission coils are switched in accordance with the position ofa movable stage. Therefore, power can be supplied from the basestructure to the electrical circuit on the movable stage at an arbitraryposition or timing. When a battery is mounted on the movable stage mainbody, as the battery can be floating-charged, the stage need not bereturned to a specific position for charging. A process, such asexposure, need not be interrupted. Charging does not take time. A highthroughput can be achieved by using the alignment stage apparatus.

A large battery need not be mounted on the movable stage and the stagecan accordingly be made lightweight. Therefore, the speed of the movablestage can be increased, so that a high throughput can be achieved.

The present invention can be applied to a case wherein no battery ismounted. In this case, maintenance, such as periodic battery exchange,becomes unnecessary, and a decrease in operating efficiency of theapparatus can be prevented.

Since power can be fed in a complete non-contact manner, power feedthrough an electrical cable is not necessary. The alignment accuracywill not accordingly be degraded by a cable packaging disturbance, orthe like. Since no cable is used, trouble, such as dust being producedwhen the cable is rubbed to attach to the wafer, insufficient insulationor wire disconnection due to the degrading of the jacket of the cable,and the like, are eliminated.

The alignment stage apparatus of the present invention is particularlysuitable as a stage apparatus having a flat structure.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a plan view showing the structure of an alignment stageapparatus according to the first embodiment of the present invention;

FIG. 2 is a side view of the structure of FIG. 1;

FIG. 3 is a view for explaining power feeding by electromagneticinduction in the structure of FIG. 1;

FIG. 4 is a view for explaining signal transmission/reception byelectromagnetic induction according to the second embodiment of thepresent invention;

FIG. 5 is a plan view showing the structure of an alignment stageapparatus according to the third embodiment of the present invention;

FIG. 6 is a side view of the structure of FIG. 5;

FIG. 7 is a plan view showing the structure of a conventional alignmentstage apparatus;

FIG. 8 is a side view of the structure of FIG. 7;

FIG. 9 is a view for explaining power feeding by electromagneticinduction of the conventional example of FIG. 7;

FIG. 10 is a front view showing a structure of an exposure apparatuswhich uses an alignment stage apparatus of the present invention; and

FIG. 11 is a flowchart for explaining the flow of a device manufacturingprocess which uses the exposure apparatus of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described.

First Embodiment

FIG. 1 is a plan view of an alignment stage apparatus according to anembodiment of the present invention, and FIG. 2 is a side view of thesame. According to this alignment stage apparatus, a plurality of powertransmission coils to supply power are buried in the base structure ofan alignment stage having a power reception coil to which an AC magneticfield is to be applied to obtain power in a non-contact manner. Thealignment stage apparatus is provided with a means for sequentiallyswitching the power transmission coils in accordance with the positionof the stage.

More specifically, in the alignment stage apparatus of FIG. 1, coils 2are arranged like a matrix in a base structure 1. Permanent magnets 12are similarly arranged like a matrix under a movable stage main body 3.When a current is supplied to the driving coils 2, the movable stagemain body 3 obtains a thrust by the Lorentz force and is driven.

An electrostatic chuck 6, which holds a wafer by the electrostatic forceand various types of sensors 4, e.g., a sensor for monitoring the lightquantity of a light source and an alignment sensor, are arranged on themovable stage main body 3.

Bearings 7 for supporting the weight of a movable stage including themovable stage main body 3, electrostatic chuck 6, various types ofsensors 4, and the like, are arranged on the lower surface of themovable stage main body 3. The movable stage is guided by the bearings 7in a two-dimensional direction along the surface of the movable stagemain body 3 whose flatness is compensated for. Alternatively, the weightof the movable stage can be supported by the Lorentz force. In thiscase, magnets are arranged on the lower surfaces of the bearings 7 aswell.

Two bar mirrors 5 are arranged on the movable stage main body 3 to beperpendicular to each other. A laser interferometer 8 mounted on aninterferometer support 13 measures the position of the movable stage. Astage controller (not shown) supplies a current to the driving coils 2to align the movable stage such that the measurement position coincideswith a target value provided by a host control device (not shown). Inthe stage structure shown in FIG. 1, a plurality of power transmissioncoils 17 (17-1, 17-2, . . . , and 17-18) are buried in the basestructure 1 to be able to feed power constantly at an arbitrary positionin a non-contact manner to the electrostatic chuck 6 and various typesof sensors 4 on the movable stage main body 3. The power transmissioncoils 17 can be provided independently of the stage driving coils 2. Inthis embodiment, the X-direction driving coils 2 also serve to feedpower. A power reception coil 15 is supported by a power reception coilsupport member 16 and arranged on the side surface of the movable stagemain body 3.

Switching means 19 for sequentially switching the power transmissioncoils 17 in accordance with the position of the power reception coil 15,that is, the position of the movable stage main body 3, is connected tothe power transmission coils 17. The switching means 19 has switches(SW1 to SW18) for the corresponding power transmission coils 17. A powerfeed signal 20 and stage driving signal 21 are connected to each switch.The switches SW1 to SW18 are controlled by a switching signal 22 inaccordance with the position of the movable stage main body 3.

When the movable stage main body 3 and base structure 1 have thepositional relationship as shown in FIG. 2, the power transmission coil17-1 and power reception coil 15 oppose each other. Thus, the switch SW1is switched to the power feed signal side, and the coil 17-1 is used asthe power transmission coil 17. The coils 17-2 and 17-3 oppose neitherthe power reception coil 15 nor permanent magnets 12, and canaccordingly be used as neither power feed coils nor driving coils.Therefore, the switches SW2 and SW3 are connected to neither the coil17-2 nor 17-3, but are open.

The coils 17-4 to 17-10 oppose the permanent magnets 12 on the lowersurface of the stage main body 3. Thus, the switches SW4 to SW10 areswitched to the driving signal side and used as the driving coils 2. Theposition of the movable stage main body 3 is measured by the laserinterferometer 8. When the switching signal is controlled in accordancewith the position of the movable stage main body 3, the powertransmission coils 17 can be switched between power feeding and drivingadequately. In this manner, the power transmission coils 17 arranged inthe base structure 1 can also be used as the coils 2 to drive themovable stage main body 3.

As shown in FIG. 3, power is transmitted by electromagnetic inductionbetween the power electromagnetic induction between the powertransmission coils 17 and power reception coil 15. To transmit the powerfeed signal, an AC power supply 27 of several kHz to several tens of kHzis used. The power induced in the power reception coil 15 is connectedto a load, such as a rectifying circuit 23, and used as a power supplyfor the electrostatic chuck 6 and sensors 4. If the frequency of the ACpower supply 27 is set at a resonance frequency determined by the mutualinductance of the two types of coils, i.e., the power transmission coils17 and power reception coil 15, and a load (rectifying circuit), powercan be transmitted the most efficiently.

Second Embodiment

FIG. 4 shows transmission and reception of a control signal usingelectromagnetic induction. The electrostatic chuck 6 and sensors 4 aremounted on the movable stage main body 3 of FIGS. 1 and 2. The controldevice (not shown) provided to the stationary side (base structure side)must also transmit and receive a signal to and from the electrostaticchuck 6 and sensors 4. When exchanging the wafer, voltage application tothe electrostatic chuck 6 is disconnected to release a chucked wafer. Achuck on/off circuit 25 is provided for this purpose. An analog signalloaded from the sensors 4 is converted into a digital signal by an A/D(analog-to-digital) converter 24.

If transmission/reception circuits 26 are respectively provided to powertransmission coils 17 and a power reception coil 15 and communicate witheach other by superposing signals on the coils 17 and 15 to which poweris supplied, the control signal can be exchanged by electromagneticinduction. As a power feed signal uses a frequency of several kHz toseveral tens of kHz, the control signal uses a high-frequency signal ofseveral hundred kHz to several MHz, which does not interfere with thefrequency of the power feed signal.

Third Embodiment

FIG. 5 shows the third embodiment of the present invention. In the firstembodiment, only one power reception coil 15 is provided. When themovable stage main body 3 moves, the power reception coil 15 graduallyshifts from the position where it opposes the coil 17-1. Accordingly,power transmission efficiency by means of electromagnetic inductiondecreases.

In order to compensate for this, a power reception coil 15 a is added inthe second embodiment. The power reception coil 15 a is arranged to bephase-shifted from power transmission coils 17. When the two powerreception coils, i.e., a power reception coil 15 and the power receptioncoil 15 a, are arranged in the traveling direction of the stage, if thepower reception coil 15 a is phase-shifted from the power transmissioncoils 17 by 90°, the fluctuations (ripple) of the total power of the twodifferent-phase coils can be decreased. Similarly, when three powerreception coils can be arranged in the traveling direction, if thephases of the coils are shifted from each other by 60°, the fluctuationsof the total power of the three different-phase coils can be decreased.In this manner, the power reception coils and power transmission coilsare arranged to be phase-shifted from each other by 180°/n where n isthe number of power reception coils in the traveling direction of thestage. Regarding the phase, when the power reception coil and powertransmission coil oppose each other like the power reception coil 15 aand power reception coil 17-1 do in FIG. 5, the phase is 0°. When thepower reception coil and power transmission coil are shifted from eachother by ½ the pitch of the transmission coils 17, like the powerreception coil 15 and power reception coil 17-13 do, the phase is 90°.In other words, the shift of one pitch of the power transmission coils17 corresponds to a 180°-phase shift. To arrange with a phase shift of180°/n is to multiply the gap between one power reception coil and anadjacent power reception coil by (K+½n) (where K is an integer of 1 ormore) or (K=½n) one pitch of the power transmission coils 17.

When a movable stage main body 3 and base structure 1 have a positionalrelationship, as shown in FIG. 5, switches SW1 and SW4 to SW10 areswitched into the same state as in the first embodiment.

In FIG. 5, as the coil 17-13 is also used as a power transmission coil,a switch SW13 is switched to the power feed signal side by a switchingsignal. Remaining switches SW2, SW3, SW11, SW12, and SW14 to SW18 areset at the neutral position in the same manner as shown in FIG. 1.

When the movable stage main body 3 moves in the X direction (to theright) in FIG. 5, the coil 17-1 is gradually shifted from the positionwhere it opposes the power reception coil 15, and accordingly, the powertransmission efficiency decreases. To the contrary, the coil 17-13 isapproaching a position where it opposes the power reception coil 15 a,and accordingly, the power transmission efficiency gradually increaseson this side. In this manner, when the two power reception coils arearranged to be phase-shifted from each other and the power as the sum ofthe two coils is fed, power can be supplied constantly, stably,regardless of the position of the movable stage main body 3.

After the movable stage main body 3 further moves in the X direction (tothe right) in FIG. 5 so that the power reception coil 15 reaches theintermediate position between the coils 17-1 and 17-2 (to have the samepositional relationship as that of the power reception coil 15 a andcoils 17-12 and 17-13 of FIG. 5), when the movable stage main body 3 isto further move in the X direction (to the right) in FIG. 5, the switchSW1 is switched to the neutral position to disconnect the powerreception coil 15 from the power feed signal and the switch SW2 isswitched to the power feed signal side so that the coil 17-2 is used asthe power transmission coil. The switching timings of the switches SW1and SW2 can be the same or different. If the switching timings of theswitches SW1 and SW2 are shifted to make a time point where both theswitches SW1 and SW2 are connected to the power feed signal sidesimultaneously, power can be fed to the power reception coil 15 throughthe two power transmission coils 17. This can suppress a decrease inpower to be fed, particularly when only one power reception coil 15 isused, as in the first embodiment.

The driving coils may be switched in the same manner as in the prior artof FIGS. 7 and 8.

Fourth Embodiment

In FIG. 5, power reception coils 15 b and 15 c, and a switching means 19a are arranged in the Y direction as well. When the movable stage is tomove in the X direction, power is supplied to a power transmission coil,which opposes the power reception coils 15 b and 15 c, and is long inthe X direction. When the movable stage is to move in the Y direction,power is supplied to a power transmission coil (in the state of FIG. 5,the coil 1 and a coil 12 or 13), which opposes the power reception coils15 and 15 a, and is long in the X direction. Then, the powertransmission coils need not be switched, and a switching sequence can besimplified.

The third and fourth embodiments can naturally be combined.

Fifth Embodiment

When a battery 11 is used, as shown in FIG. 5, power can be suppliedconstantly, stably. In the fifth embodiment, since constant powerfeeding is possible, no large batteries are needed, and a compact,lightweight battery can be employed.

When a battery is to be mounted on a movable stage, power, which hasbeen fed, may be stored once in the battery and then fed from thebattery to the respective portions in the movable stage. Then, due tofluctuations in power consumption in the movable stage or a decrease inpower transmission efficiency as a result of the positional relationshipbetween the power reception coil 15 and power transmission coils 17, ifthe power consumption in the moveable stage exceeds the power feed,power can be supplied to the respective portions in the movable stagestably. Power is fed to the movable stage at an arbitrary position ortiming. Even during a process such as exposure, the battery is chargedat a position or timing when the power feed exceeds the powerconsumption. The necessity to move the movable stage to a specificposition for the purpose of charging, to delay the start of a process,such as exposure, or to interrupt the process, is very small. Thebattery is constantly capable of being floating-charged and accordingly,requires no extra time for charging.

To employ the battery 11, as well, is particularly effective when onlyone power reception is provided, as in the embodiment shown in FIG. 1.

As described above, according to the above embodiments, a large batteryneed not be mounted on the movable stage and the stage can accordinglybe made lightweight. Therefore, the speed of the movable stage can beincreased, so that a high throughput can be achieved. Since power can befed in a complete non-contact manner, power feed through an electricalcable is not necessary. The alignment accuracy will not accordingly bedegraded by a cable packaging disturbance, or the like. Since no cableis used, trouble, such as dust being produced when the cable is rubbedto attach to the wafer, insufficient insulation or wire disconnectiondue to the degrading of the jacket of the cable, and the like, areeliminated. The above embodiments are particularly suitable to a stageapparatus having a flat structure.

Sixth Embodiment

FIG. 10 shows a semiconductor device manufacturing exposure apparatus,which uses the alignment stage apparatus described above as a waferstage.

This exposure apparatus is used for the manufacture of a device having afine pattern such as semiconductor device, e.g., a semiconductorintegrated circuit, a micromachine, a thin film magnetic head, or thelike. Exposure light (this term is a generic term for visible light,ultraviolet light, EUV light, X-rays, an electron beam, a chargedparticle beam, and the like) as exposure energy from a light source 61through a reticle R, as a master, irradiates a semiconductor wafer W asa substrate via a projection lens (this term is a generic term for arefracting lens, a reflecting lens, a catadioptric lens system, acharged particle lens, and the like) 62 as a projection system, to forma desired pattern on the substrate.

In this exposure apparatus, a surface plate 51 has a multi-phaseelectromagnetic coil (the coils 17 of FIG. 2), and a moving stage 57 haspermanent magnets (the permanent magnets 12 of FIG. 2) group.

The moving stage 57 (the movable stage 3 of FIG. 2) is supported byhydrostatic bearings 58 (the hydrostatic bearings 7 of FIG. 2). Themovement of the moving stage 57 is measured by using a mirror 59 (thebar mirrors 5 of FIG. 2) fixed to the moving stage 57, and aninterferometer 60 (the laser interferometer 8 of FIG. 2).

The wafer W as the substrate is held on a chuck (the electrostatic chuck6 of FIG. 2) mounted on the moving stage 57. The pattern of the reticleR as the master is reduced and transferred onto the respective regionson the photoresist-coated wafer W by the light source 61 and projectionlens 62 by the step and repeat scheme or step and scan scheme to form alatent image pattern on the photoresist.

The alignment stage apparatus of the present invention can similarly beapplied to an exposure apparatus that forms a latent image pattern on aphotoresist without using a mask, but by drawing a circuit patterndirectly on a semiconductor wafer.

A semiconductor device manufacturing process using this exposureapparatus will be described. FIG. 11 is a flowchart showing the flow ofthe entire semiconductor device manufacturing process. In step 1(circuit design), the circuit of a semiconductor device is designed. Instep 2 (mask fabrication), a mask is fabricated on the basis of thedesigned circuit pattern.

In step 3 (wafer manufacture), a wafer is manufactured using a materialsuch as silicon. In step 4 (wafer process), called a preprocess, anactual circuit is formed on the wafer by the above exposure apparatus inaccordance with lithography. In the next step, step 5 (assembly), calleda post-process, a semiconductor chip is formed from the wafer fabricatedin step 5. This step includes processes such as assembly (dicing andbonding) and packaging (chip encapsulation). In step 6 (inspection),inspections including an operation check test and a durability test ofthe semiconductor device fabricated in step 5 are performed. Asemiconductor device is finished with these steps and delivered.

The wafer process of step 4 includes the following steps, i.e., anoxidation step of oxidizing the surface of the wafer, a CVD step offorming an insulating film on the wafer surface, an electrode formationstep of forming an electrode on the wafer by deposition, an ionimplantation step of implanting ions in the wafer, a resist process stepof applying a photosensitive agent to the wafer, an exposure step oftransferring the circuit pattern to the wafer after the resist processstep by the exposure apparatus described above, a developing step ofdeveloping the wafer exposed in the exposure step, an etching step ofetching portions other than the resist image developed in the developingstage, and a resist removal step of removing any unnecessary resistafter etching. These steps are repeated to form multiple circuitpatterns on the wafer.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the claims.

CLAIM OF PRIORITY

This application claims priority from Japanese Patent Application No.2004-016857 filed Jan. 26, 2004, the entire contents of which are herebyincorporated by reference herein.

1. An alignment stage apparatus including a base structure and a movablestage which can move along a surface of the base structure so as not tobe in contact with the base structure, said apparatus comprising: aplurality of power transmission coils buried under the surface of thebase structure; a power reception coil attached to the movable stage tooppose the surface; a switch unit configured to sequentially switch, ofsaid plurality of power transmission coils, those that are to beenergized to feed power in accordance with a position of the movablestage; and a power feed unit configured to supply AC power to said powertransmission coils to be energized through said switch unit, whereinsaid power reception coil comprises a plurality of power reception coilsarrayed in a driving direction of said movable stage, and said powerreception coils and power transmission coils are phase-shifted from eachother by 180°/n where n is the number of power reception coils arrayedin the driving direction of said movable stage.
 2. An alignment stageapparatus including a base structure and a movable stage which can movealong a surface of the base structure so as not to be in contact withthe base structure, said apparatus comprising: a plurality of powertransmission coils buried under the surface of the base structure; apower reception coil attached to the movable stage to oppose thesurface; a switch unit configured to sequentially switch, of saidplurality of power transmission coils, those that are to be energized tofeed power in accordance with a position of the movable stage; and apower feeding unit configured to supply AC power to said powertransmission coils to be energized through said switch unit, wherein afrequency of the AC power is set at a resonance frequency determined bya load and a mutual inductance of said power transmission coils and saidpower reception coil.